1. Field of the Invention
The present invention relates to an improvement in a unit integrated system including an electronic control unit and a hydraulic unit which are formed integrally and to a connector for a vehicle-mounted system such as an ABS (antilock brake system), a TCS (traction control system) and the like.
2. Description of the Prior Art
One of the systems for enhancing the safety of automotive vehicles is an ABS for preventing wheel lock when the brakes are applied suddenly or on a slippery road. In general, conventional ABSs have been constructed such that a hydraulic unit is disposed in the engine room and an electronic control unit is disposed in the cabin, for example, under seats or within front panels.
However, separate provision of the hydraulic unit in the engine room and the electronic control unit in the cabin requires wiring harnesses extending from the engine room to the cabin for electrical connection between the hydraulic unit and the electronic control unit, resulting in elongated wiring harnesses and complicated operation of laying the harnesses.
Recently, it has been proposed to provide the electronic control unit and hydraulic unit which are integrated together in the engine room for reduction in length of the wiring harnesses and simplification of the laying operation of the harnesses in an assembly line. Such an integrated system is disclosed in, for example, Japanese Patent Application No. 3-177132 (1991).
In the above-mentioned system in which the hydraulic unit and the electronic control unit are integrated, mere combination of the two units causes difficulty in pouring oil into the hydraulic unit, depending upon size and positions of the two units.
Typically, oil is poured into the hydraulic unit through a hydraulic pipe connected to an oil inlet provided on an upper surface of the hydraulic unit. As shown in FIG. 19, for system size reduction, an electronic control unit 102 is assembled to the hydraulic unit 101 having the oil inlet on its upper surface in juxtaposition with each other. In the assembling, if an upper surface 102a of the electronic control unit 102 is higher than an upper surface 103a of the hydraulic unit 101, since connection of a hydraulic pipe 134 to the oil inlet of the hydraulic unit 101 with an existing spanner-shaped piping tool (not-shown) necessitates a space enclosed by broken lines 135 of FIG. 19 for operation of the tool, the piping tool interferes with an upper part 102b of the electronic control unit 102 extending upwardly above the upper surface 103a of the hydraulic unit 101, resulting in impracticable piping connection. One of the solutions of this problem is the use of a separately developed piping tool for exclusive use, which however requires additional labor and costs.
Further, in the conventional assembly of the hydraulic unit as shown in FIG. 20, a flow control valve 105 and a solenoid 106 for opening and closing oil passages are mounted in a housing 103 defining the suitable oil passages, and a positioning sleeve 113 of a predetermined height L and a base plate 107 are fixed to the housing 103 by fixing bolts 129, whereby the flow control valve 105 and the solenoid 106 are mounted so that they are located in predetermined positions.
As disclosed in Japanese Patent Application No. 3-177132, a mounting portion formed in the electronic control unit is bolted in a predetermined mounting position of the hydraulic unit, to integrally form the electronic control unit and the hydraulic unit.
This requires the separate mounting portions for the electronic control unit and the hydraulic unit, and the fixing bolts and work thereof, resulting in increased size and cost.
Further, the structure disclosed in Japanese Patent Application No. 3-177132 is adapted such that a connector mounted to an end of wiring harnesses extending from the hydraulic unit is electrically connected to a group of terminals of the electronic control unit. For the purpose of insuring a waterproofing property, the connector should be a waterproof connector. However, the waterproof connector is costly and large-sized, which causes increased costs and increased size of the structure.
Another conventional unit integrated system is shown in FIG. 21 wherein the electronic control unit 102 is merely coupled to the hydraulic unit 101 on its first major surface 140. This unit integrated system has a relatively large size in a direction X in which the hydraulic unit 101 and the electronic control unit 102 are arranged, which is a significant hindrance to size reduction. This results from a large size, in the X direction, of the electronic control unit 102 which includes a junction block 110 connected to a relay 112 and disposed adjacent the major surface 140 of the hydraulic unit 101, and a printed board 109 having a control circuit incorporated therein and disposed in parallel with the junction block 110, the junction block 110 and the printed board 109 being arranged in the X direction.
The foregoing unit integrated system may achieve size reduction by integration of the hydraulic unit 101 and the electronic control unit 102, but does not meet the requirement of further size reduction because of its large size in the X direction.
Referring to FIG. 21, the electronic control unit 102 further includes a case 160 (170) which houses and protects the junction block 110 connected to the relay 112 and electronic components such as the control circuit built-in printed board 109.
FIG. 22 is an exploded perspective view of the conventional case. The case 160 includes divided case elements 161, 162 permitted to be integrated. Through holes 163 are formed in the four corners of the divided case element 161, and through holes 164 are formed in the divided case element 162 in corresponding relation to the through holes 163. The divided case element 162 is finished in the form of a thin plate and has a groove (not shown) on its one major surface. A sealing member 165 is fitted in the groove. After the engagement of the divided case elements 161, 162, with the electronic components housed within the divided case element 161, four screws 166 are inserted in the through holes 163, 164 from above the divided case element 161 and tightened with nuts 167 from below the divided case element 162. Then the divided case elements 161, 162 are integrated into the electronic control unit 102.
FIG. 23 is an exploded perspective view of another conventional case. The case of FIG. 23 is substantially similar in construction to the case of FIG. 22 except that a divided case element 172 is finished in the form of a cup and includes an outer peripheral portion 172a having female threaded portions 174 corresponding to through holes 173 formed in the four corners of a divided case element 171, and a sealing element 175. Like reference numerals are used herein to designate parts corresponding to those of FIG. 22, and description thereof will be omitted.
In the case of FIG. 22, however, the nuts 167 project from the divided case element 162, and the projecting portions (forward ends of the screws 166 and the nuts 167) from the case 160 are obstacles in designing when the electronic control unit 102 and the hydraulic unit 101 are integrated. A need exists to determine the configuration of the hydraulic unit 101 so as not to interfere with the projecting portions, thereby lowering the degree of designing freedom. A space for the projecting portions are further required.
On the other hand, the case of FIG. 23 is adapted such that the female threaded portions 174 in the outer peripheral portion 172a of the divided case element 172 are provided to tighten screws 176, and has no portion projecting from the case 170, thereby solving the problem. However, the provision of the female threaded portions 174 requires a relatively great height of the outer peripheral portion 172a in the longitudinal direction X of the screws 176, resulting in increased size of the case 170 in the X direction. Further, the provision of the sealing member 175 in the outer peripheral portion 172a with a given strength or more insured requires a relatively great thickness t of the outer peripheral portion 172a, which is a significant hindrance to the size reduction of the case 170.
The relatively long screws 166, 176 are needed for the cases 160, 170 of FIGS. 22 and 23. For this reason, the cases 160 and 170 cannot employ commercially available general-purpose screws but require the screws 166, 176 for exclusive use which are a factor of increased cost.
A braking control device such as the ABS has been constructed as shown in FIG. 24, for example.
Referring to FIG. 24, a power supply terminal of an electronic control unit 152 is connected to a positive terminal of a battery +B having a grounded negative terminal through an ignition switch 151. A fail-safe make-break relay 153 includes a relay coil having a first end connected to the positive terminal of the battery +B through the ignition switch 151 and a second end connected to a control output terminal of the electronic control unit 152. The fail-safe relay 153 has a make contact connected directly to the positive terminal of the battery +B and a break contact grounded. A braking load 154 such as a solenoid for controlling a brake fluid pressure has a first end connected to a common terminal of the fail-safe relay 153 and a second end connected to a load control output terminal of the electronic control unit 152. A warning lamp 155 has a first end connected to the positive terminal of the battery +B through the ignition switch 151 and a second end connected to the common terminal of the fail-safe relay 153 through the anode and cathode of a back-flow checking diode 156.
The electronic control unit 152 is generally disposed within the cabin whereas the fail-safe relay 153 and the braking load 154 are disposed in the engine room. Thus connection of the electronic control unit 152 to the fail-safe relay 153, braking load 154, and ignition switch 151 is made by a wiring harness and a connector 157 shown in dashed-and-dotted line in FIG. 24.
The electronic control unit 152 receives an output signal from a wheel speed sensor for detecting the rotational speed of the respective wheels and various switch signals. For example, the electronic control unit 152 calculates the control amount of the solenoid 154 serving as a load in response to the output of the wheel speed sensor to electrify and drive the solenoid 154 through the make contact of the fail-safe relay 153 in accordance with the control amount.
In such a construction, if no electrical connection is made because the connector 157 is not connected or an abnormality occurs within the electronic control unit 152, the excitation of the relay coil of the fail-safe relay 153 is released and the common terminal of the fail-safe relay 153 is connected to the break contact. Then current flows from the battery +B through the ignition switch 151, the warning lamp 155, the diode 156 and to the common terminal and the break contact of the fail-safe relay 153, and the warning lamp 155 lights up, signalling the unconnected condition of the connector 157.
Recently, there has been an increasing demand to insure a possibly large interior space within the cabin whereas the types of the electronic control unit have increased with better performance of the automotive vehicles. The provision of the electronic control unit 152 within the cabin and the provision of the fail-safe relay 153, solenoid 154 within the engine room increase the wiring harnesses for connection between the cabin and the engine room, causing difficulty in meeting the requirement of insuring a large interior space within the cabin.
To meet the requirement, as shown in FIG. 25, a control circuit 152a and the fail-safe relay 153 are formed into the electronic control unit 152 which is then integrated with the braking load 154, and the integrated unit is disposed in the engine room.
Since the electronic control unit 152 containing the fail-safe relay 153 is placed in the engine room, the need for the warning lamp 155 of FIG. 24 is eliminated. In FIG. 25, the warning lamp 155 and diode 156 of FIG. 24 are not shown, and the break contact of the fail-safe relay 153 is grounded.
As shown in FIG. 25, the electronic control unit 152 is connected to the battery +B, the ignition switch 151, the solenoid 154, and the sensor by a single connector (indicated by open circles of FIG. 25).
In the arrangement of FIG. 25, the make-break relay is used as the fail-safe relay 153 although the warning lamp 155 is not adapted to light up by using the break contact of the fail-safe relay 153 as shown in FIG. 24. The fail-safe relay 153 is very costly, and no means indicates the unconnectedness of the connector, if occur.
In general, for feeding power or an electric signal to components within a device from the exterior of the device, a connector is mounted on a box-shaped element of the device for connection to external lines to feed power or electric signal to the components from a connecting terminal of the connector.
The connector, as shown in FIG. 58, includes a housing 751 mounted on a box-shaped element A and made of an insulative resin, and a connecting terminal 752 held by and housed in the housing 751. Connection to the components in the box-shaped element A, for example a junction block, is made through lines such as wiring harnesses 753 as shown in FIG. 58. After one end of the harnesses 753 is connected to the component, the other end of the harnesses 753 is housed in a connector housing 154 and is connected to a connector receiving portion 755.
The prior art connector, however, connects the external lines and the components within the device in one-to-one corresponding relation. Two pairs of components to be connected inside and outside the device reasonably require two connectors. The connector of FIG. 58 results in an increased number of components and an increased number of assembling steps for connection of the connectors.
This type of connector may be constructed such that the connector housing made of an insulative resin for housing and holding the connecting terminal is mounted on the box-shaped element of the device while being exposed to the exterior of the device, and the terminals of the connector and the components are connected by soldering or the like within the device.
Unfortunately, such a connector cannot readily make the connection of the terminals of the connector and the components within the device by soldering. The result is an increased number of connecting steps between the connector and the components within the device.
Further, in the connector of FIG. 58, since the components within the device are connected by lines such as the wiring harnesses 753, it is necessary to initially connect one end of the harnesses 753 to the components and thereafter to house the other end of the harnesses 753 in the connector housing 754 and connect it to the connector receiving portion 755. This necessarily increases the number of components and the number of assembling steps.
In the above-mentioned case, the connection of the connector and the electrical components is often made by using a junction block in terms of reduction in the number of lines of the wiring harnesses for connection, decrease in diameter of the wiring harnesses by joint reduction, and facilitation of fabrication. The connection is often made through the junction block in the case where the junction block is not particularly required.
This is because the connection of the connector and the components without using the junction block increases the number of connectors for connection, resulting in increased costs, an increased number of assembling steps, and deterioration of working efficiency.
However, the constant connection through the junction block, if not required, causes the junction block to grow larger more than necessary and increases the amount of bus bars to be used. The result is increased costs of the junction block itself, and a large area of the junction block in the device.
Further, the connector for connecting the electrical components by the lines such as the harnesses 753 as shown in FIG. 58 requires some space for connection. It is difficult to connect the electrical components positioned very close to the connector.
In particular, connection by the harnesses is made in such a manner that the harnesses are initially connected to one of the connector and the electrical components and then connected to the other. This necessarily increases the number of assembling steps.